User`s guide

Section Five - AT Command Set

5.1 Executing Commands

Your modem is in Command Mode upon power-on and is ready to receive

and execute “AT” commands. The modem remains in Command Mode until it

makes a connection with a remote modem. Commands may be sent to the modem

from an attached terminal or a PC running a communication program.

This modem is designed to operate at common DTE speeds ranging from

115.2Kbps (or 57.6Kbps) to 300bps. All commands and data must be issued to

the modem using one of the valid DTE speeds.

5.2 Command Format

All commands must begin with the AT prefix, followed by the command

letter and ended with the ENTER key. Spaces are allowed in the command string

to increase command line readability, but are ignored by the modem during

command execution. All commands may be typed in either upper or lower case,

but not mixed. A command issued without any parameters is considered as

specifying the same command with a parameter of “0”.

Example: ATL [ENTER]

This command causes your modem to lower its speaker volume.

5.3 AT Commands: Basics

ATtention (AT) commands are the means by which you control and monitor

a modem. Typically, the communication applications automatically issues them,

and you need not know the commands and their options.

However, to custom-configure the modem for an application, or to optimiz

performance, you can issue commands through the communucations applica-

tion yourself. In most communications applications, there is a menu item, or

option, for entering extended or custom AT commands. See your communica-

tions application documentation.

You can also configure the modem by issuing AT commands directly from

a simple terminal-emulation application . One such application is HyperTerminal,

which is present on computers that have windows.

To issue an AT command from the terminal-emulation application, you must

ensure that the modem is in command mode (in which it can detect and respond